Hitchhiker's Guide to Streaming Media: Making Flash Play
A SWF file doesn't need to contain the video file: SWF files may include video content that has been imported from FLV or F4V files, or may merely reference external FLV/F4V video files which the SWF file will play back at certain pre-defined or user-input intervals. It's important to remember, though, that SWF files can be set up to automatically launch, due to their interactive nature, while a stand-alone FLV / F4V needs to be prompted to play.
So when my friend, who didn't have AMP loaded on her machine, clicked on the FLV file, it imported the video file into Flash Professional as an object. This object was available to be placed on a Flash timeline, wrapped with a video player and then exported as a SWF file.
FLA
The final piece of the puzzle is the FLA extension. An FLA file is the file that Flash Professional creates that acts as the programming file for Flash Professional. In other words, while an SWF file is the self-contained interactive output file from Flash Professional, which Flash Player will play back, an FLA file is one that the programmer or developer will use to generate the SWF files.
"So SWF is definitely what we want," my friend wrote a bit later. "No one has created an SWF file for our Flash video files, and I think a version of the encode with a basic player in it sounds good - so people can just click 'go' and the video will start."
Now that we had determined what kind of file my friend needed—a SWF file with an embedded video file—there was still one more option: which application to use to generate the SWF file.
Flash Professional
Adobe's Flash Professional is the best way to create customized players, but even Adobe acknowledges that not every one may want to learn this developer-friendly program with its programming language and somewhat befuddling timeline. As such, Adobe recently announced Strobe, a new media video player framework that provides a plug-in model that suggests "standards" for player behavior types (classes, in Flash parlance). It won't create a simple player for you, but it will provide a shortcut that eliminates the need to rewrite the entire player.
FlixPro
On2's Flash 8 Video (On2 VP6-E and VP6-S) encoder also has the ability to generate SWF files as well as FLV files. The SWF files embed the video in a controller-less player that has three options: play immediately, play after a particular number of seconds delay, or stop on first frame. This tool is good for those who might want to generate SWFs that are going to be embedded directly in to a simple HTML page to play back short video files, but the lack of controller means that long-form content may not be the best choice for this option.
To address this, the newer versions of FlixPro have Those who want to create custom players (or "skins") can create them in Flash Professional and then pre-load a series of skins within FlixPro's "Player Skin Options" to output with a particular video file encode, using the export player feature.
Sorenson Squeeze
The makers of Sorenson Spark, the original Flash Video codec, are also the creators of Squeeze, a multi-format transcoding software tool. Besides the ability to output a variety of QuickTime, Real and Windows Media files, Squeeze can also generate FLV and F4V files. Squeeze can embed Spark, VP6 and H.264 content within a SWF file through a variety of skins. Over the last few years that Squeeze has been available, Sorenson also has been asked to "improve upon the slightly outdated SWF player templates included in Squeeze" as noted on a recent support request. The company has complied and created "re-skinned" a couple of the templates, complete with controls, to feel a bit more modern and more usable.
In addition, for very long-form content, Squeeze also offers the option of "stitching" for large SWF files, which breaks larger / longer video files in to smaller SWF files which play in succession like one long movie instead of a series of short videos.
So that's a short overview of FLA, FLV, F4V, and SWF files, as well as how each fit with in the picture of Flash and Flash video files. Hopefully this explanation will help you understand the differences, so that you can, well, just create a Flash video file and play it back.